1. Technical Field
The invention relates to a vehicle navigation system having a map database storing map data, a method of generating a map database, and a method of processing data stored in a map database. The invention relates in particular to such systems and methods in which a map database may include attributes.
2. Related Art
Navigation systems are known which determine a route from a starting point to a destination using map data. Generally, these navigation systems may perform a search for a route which minimizes a cost function. The cost function may represent travel time, distance or fuel costs associated with the route, or any other suitable quantity to be minimized. The route which is optimum may depend on the activation of prefer or avoid options. Prefer and avoid options for highways, ferries or tunnels may be provided.
In addition to route determination, navigation systems may also provide route guidance functions via a user interface. The provision of guidance information may involve the generation of video or audio output which provides information on a portion of a road network surrounding the vehicle, possibly combined with video or audio directions to a driver.